Or you could look at their PvP stats... Seriously if they can excel in PvP then they have grasped the controls and are able to determine when to commit or disengage from a fight. Hitting difficult targets in PvP makes PvE a joke, it's funny to see just how slow people with low k/ds switch from precision spot to precision spot on targets, if they hit it at all. They will sit in high danger zones, fall off the edge, and then not reload all their weapons in the shield bubble. TLDR: Good PvP players always translate into good PvE players, same can't be said the other way around.